Saturday, 5 June 2010

THE first big study on barefoot running in Nature : Death to Heel striking.
The barefoot debate is about to get a little bit hotter.

A new study released this year by Lieberman in Nature takes an evolutionary look at barefoot running. In the study, they compared barefoot and shoe running on a whole variety of factors in both regular shoe wearers, regular barefoot runners, and even Kenyans!

This is a timely piece as it adds more evidence to the article I wrote a couple days ago below. The implications are great as they extend beyond barefoot running to foot strike too (heel vs. forefoot, etc.) I’ll highlight some of the findings.

Foot strike and Elastic response and energy transfer:
As I speculated in my article, footstrike greatly effects the elastic energy return. In their study, it was found that forefoot and some midfoot strikes “reduces the effective mass of the foot and converts some translational energy into rotational energy; the calf muscles control heel drop, and the FFS runner can take fuller advantage of elastic energy storage in both the Achilles tendon and the longitudinal arch of the foot.”
On this topic, Liberman speculates that the arch plays a key role in reduced oxygen cost of running in barefoot runners. Essentially during a mid/fore foot strike the arch can stretch over the entire first half of the stance phase, while during the rearfoot strike, it has to wait until the last part of this phase, thus decreasing energy storage and return.

Also, forefoot and some midfoot strikes allowed for greater energy transfer. When heel striking a large portion of kinetic energy dissipates. With forefoot striking, some of the translational kinetic energy converts into rotational energy.